A laser radar system includes a single-beam narrow-band laser and a receiving system. The laser generates and emits a beam of light pulse, which hits an object and is reflected back, and is finally received by a receiver. The receiver accurately measures a transmission time of the light pulse from being emitted to being reflected. Since the light pulse is transmitted at a velocity of light, the receiver always receives the previously reflected pulse before next pulse is emitted. In view that the velocity of light is known, the transmission time can be converted into a measurement on distance. With reference to a height of the laser, a laser scanning angle, a position of the laser obtained from a GPS, and a laser emission direction obtained from an inertial navigation system (INS), coordinates X, Y and Z of each ground spot can be accurately calculated. An emission frequency of a laser beam may range from several pulses per second to tens of thousands of pulses per second. For example, for a system with a frequency of 10,000 pulses per second, the receiver may record 600,000 points in one minute. In general, the ground spot spacing of the laser radar system varies from 2 m to 4 m.
The current laser radar system mainly uses a single-beam narrow-band laser as an emitter, which has a small detection range and a low speed. A multi-beam narrow-band laser can expand the detection range of the laser radar, and greatly shorten the scanning speed.